


Permanence

by BarkingPup



Category: Swapfell - Fandom, Undertale (Video Game)
Genre: Dubious Consent, Ecto-Penis (Undertale), Ecto-Tongue (Undertale), Ecto-Vagina (Undertale), Grooming, M/M, Non-Consensual Body Modification, Omg these tags exist, Possessive Behavior, Stockholm Syndrome, creepy sans
Language: English
Status: Completed
Published: 2017-04-01
Updated: 2017-04-01
Packaged: 2018-10-13 17:16:06
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 2,840
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10518255
Author URL: https://archiveofourown.org/users/BarkingPup/pseuds/BarkingPup
Summary: Sans takes impeccable care of his possessions.





	

**Author's Note:**

> Dipping my toes into NSFW. If you see anything that needs improvement, let me know!

Sans closes the front door with a slam and a sigh, shoulders drooping. He groans, leaning against the crooked aperture. They never did fix the stupid thing but honestly, on his long list of things to do it had never been very high. Plus a window would break or a trap would rust and it’s not like they heated the house much anyways. He looks up at the clack of bare feet on wood and grimaces.

 

“do you have to walk around naked like that?”

 

Papyrus kneels at his master's feet and glances up with a lazy smile. “No idea what you’re talking about, mi’lord.”

 

Sans braces himself against the door and holds up a boot. Papyrus’ slow and deliberate unlacing is soothing to watch, each long elegant digit scarred and sharpened. 

 

“you know very well what I mean, mutt.”

 

Papyrus pulls off the steel toe boot and carefully places it to the side, perfectly straight in that odd, obsessive way Sans secretly loves. Said skeleton lifts the other boot and watches Papyrus take it apart. 

 

“What better way to show off mi’lord’s artwork?”

 

Sans hums noncommittally. Really, Papyrus’ obsession with the carvings he had done was kind of embarrassing. Papyrus pulls off the second boot and places it parallel to the other, folding his hands in his lap, waiting. Sans drops his bag, the tools clattering inside, just to watch the grimace on Papyrus’ face. 

 

“Mi’lord…”

 

Sans snickers and makes sure to kick the taller skeletons femur as he passes. Papyrus sighs, unfolding himself and picking up the messenger bag to hang it on the designated hook. Sans flops onto the couch and groans, stretching. Stars, that felt good. 

 

“No bites today, mi’lord?”

 

Sans growls, grinding his teeth. “ugh, no. some of the traps were broken though. i think that group of idiot teens is doin’ it. gonna give em a beating next time i see the bastards.”

 

Papyrus walks to the couch and kneels, brow bones furrowed. “Are you sure that’s wise, mi’lord? They are many and you are only one.”

 

Sans grabs the leash attached to his mutts’ collar and pulls, forcing Papyrus to brace himself against the cushions so his knees don't leave the ground. “you callin’ me weak, mutt?”

 

Papyrus stares into his eye flatly. “Yes, mi’lord. You  _ do  _ have only one HP.”

 

“ugh, stop trying to get me to bring you along, idiot.”

 

“Is it working?”

 

Sans digs a phalange into the gaping crack bisecting his left eye and groans. “ _ yes.” _

 

Papyrus gently curls his own fingers around the hand scratching at the old wound and pulls it away. “Please, mi’lord… do not.”

 

“sorry, sorry.”  He turns to Papyrus’ scarred and chipped phalanges and digs into it with a sigh. “it’s just so stressful. this is the second week the traps have been empty and i haven't caught no one.” 

 

Papyrus shivers as the sharpened bone digs particularly deep. “I have the utmost faith in mi’lord.”

 

Sans rolls his eyelight. “duh. but faith doesn't bring in food, now does it.”

 

“It seems to do just fine bringing mi’lord home every day.”

 

“you sap.” Sans chips off a piece of bone and watches the slow bead of marrow appear. So satisfying. He starts on another scar, clawed distals scratching at the half healed bone.

 

“ _ Ah, _ only f-for you, mi’lord.”

 

“issat so?” Sans tries to school his face but he’s terrible at the deadpan. He sinks his claws particularly deep and watches Papyrus’ hips hitch against the couch. “hmm. i dunno, mutt, after tellin’ me i’m weak…” He can feel the working side of his mouth lift. “your loyalties are in question.” The bone cricks satisfactorily and marrow starts to bead but Sans listens for the breathless gasp.

 

“Wh-what can I do to regain mi’lord’s trust?”

 

Sans leans back, dropping his ritualistic chipping of Papyrus’ phalanges. He taps a claw on his three replacement teeth, the scarred, overgrown bone clicking pleasantly. Papyrus’ hazy, dilated eyelights are drawn to the movement, as Sans knew they would. The guilt that draws his brothers brow down, that tugs the corner of his lazy smile, that clenches his hands on the cushions, is a sweet, sweet victory. Papyrus knows his sins are not forgiven. Sans makes sure of that.

 

“mmmmm.” Sans stretches out a foot, forcing Papyrus back. “how’s about you start by undressin’ me, mutt.” He makes sure his sock clad heel digs into his brothers pubic symphysis.

 

Papyrus hisses but knows better than to twitch. “ _ Hhhh _ \- of c-course mi’lord.”

 

Sans watches as the chipped and scarred phalanges delicately, always so delicate around his weak, one HP brother, pushes up his pant leg to grasp at the top of his sock. His bones are flushed so prettily, slightly tacky as whatever the bastard Gaster made them of reacts to the arousal. It’s unfortunate he can’t make his mark on Papyrus’ face because the swooping curls and flowers he carved into his clavicle look  _ good _ . The small fractures, healed crookedly, on the left side of his skull were an accident. Before he knew how to do it properly. When he was delirious from pain so much pain and he just  _ wanted his teeth back _ . 

 

“Mi’lord?”

 

Sans blinks. 

 

His socks are in a neatly folded pile beside the couch, Papyrus leaning forward, hands frozen on his belt. Sans feels the trickle of marrow across his phalanges and pulls his sharpened bones with a sucking sound from Papyrus’ jaw. 

 

_ Papyrus LV 5 HP 1299/1300 _

_ Belongs to you. _

 

Sans licks at his dripping digits, relishing in the acrid burn. He feels Papyrus’ claws dig into his belt and grins.

 

_ Plip… plip… _

 

“whatchya waitin’ for, mutt?”

 

His brother looks so beautiful stained in his insides. Each drip drip of dark red running through the cracks and pits and carvings in complicated patterns. He digs his calcaneus into Papyrus’ pelvis and watches his face twitch. The bone is hot beneath it and he grinds harder. Papyrus pauses, hands frozen in pulling out Sans’ belt. 

 

“tsk, giving up already?” He presses and watches his brothers toes curl.

 

“N-no  _ haaah… _ m-mi’lord.”

 

He can hear him grinding his teeth from here. The three metal replacements click click clicking against the bone.

 

“hm. convince me.”

 

“ _ Ahhh _ y-yes mi’lord.”

 

Still so deliberate, so careful. Steady despite the growing tackiness of his pelvis beneath Sans’ heel. Papyrus pauses, unable to pull the pants down any further without Sans lifting his hips. There’s a quirk of a brow, blurry eyelights rolling upwards and Sans grins (but only smirks, always smirking because  _ he broke it _ ). 

 

“sumthin’ wrong, mutt?”

 

Sans has never not helped and the confusion, the slight panic is  _ beautiful. _

 

“I-I… m-mi’lord?”

 

Papyrus’ phalanges curl around the waist, brushing Sans’ ilium and he hisses at the bolt of pleasure. Papyrus’ hips jerk into Sans’ heel and he freezes. Sans glares.

 

“did i say you had permission?”

 

“S-sorry, mi’lord.”

 

_ CRACK _

 

“shut up.”

 

_ Papyrus LV 5 HP 1298/1300 _

_ Belongs to you. _

 

“you’re disgusting.”

 

Papyrus gazes up at him, the new scratches across his skull slowly beading with dark red. He shivers, fingers tightening on Sans’ pants, brushing his ilium again. 

 

“Y-yes, mi’lord.”

 

Sans groans, hips twitching. “ _ f-fuck. _ ” He lifts himself off the couch. “take 'em off, mutt.”

 

Papyrus pulls and his knuckles skate across Sans’ femurs, lightly brushing the insides. Sans gasps at the feathery touch, biting down on a moan. As soon as his pants are past his knees he drops himself back down, his own bones becoming tacky with pleasure. Miffed, he grinds his heel into Papyrus’ symphysis hard enough to see his brother wince. He lifts his leg just enough for the pants to get folded away then spreads them. Papyrus eyes the slowly gathering magic at his pelvis hungrily, trembling with the effort of staying still. 

 

He trained his mutt well.

 

Sans reaches out to the dropped leash on the cushion beside him. He fingers the well worn leather, remembering earlier days when it had to be chain lest his mutt get… ideas. He pulls, Papyrus’ d-ring clinking as he follows forward.

 

“you know what to do.”

 

Papyrus’ grasps his femurs, the prick of his sharpened distal phalanges sending sparks down his spine. Sans lifts his legs and rests them on his mutts' shoulders, pulling the leash taut. His brothers breath is hot, brushing across his pubis and fuck he just wants to shove his fucking face in there. Sans reaches down to do just that when Papyrus  _ licks. _

 

“ _ Ahhah.”  _ He twitches, hand coming to rest on his mutts' tacky skull. Papyrus licks again, running his long, wet tongue from bottom to top. “ _ F-fu-ahh.” _  Sans clenches his femurs around Papyrus’ skull, hunching as he shivers at every sloppy run. His toes curl when Papyrus moves toward his ischium, tongue wrapping around the gaps. 

 

The magic pools faster, gaining solid shape, and Sans whines as he grinds into nothing. Papyrus’ moves to the other side, tongue curling and undulating and every dripping touch sends shivers through his pelvis.  _ Finally,  _ Papyrus licks the newly created pussy and Sans digs his claws into his brothers skull, hips bucking. 

 

“ _ nnnn-ahhh!”  _

 

Papyrus licks harder, pressing inside and brushing over Sans clit with every stroke. The couch is soaked, the heady smell of acrid magic and arousal thick in the tiny room. Sans grinds onto his mutts' tongue, gasping at another bolt of pleasure. The leash goes slack with a thump and Sans blinks hazily at it. No.

 

NO.

 

With a snarl, he digs his sharpened phalanges into his brothers skull and forcibly pulls him away. His mouth and teeth are stained and wet, dripping off his chin and mixing with the marrow that leaks from his injuries. His bones are flush, tongue hanging limply out of his panting mouth. He glances up at Sans, eyelights so hazy they almost fill his sockets. Sans pulls the leash up, forcing Papyrus’ head at an uncomfortable angle. 

 

“you thought you could get away with doing a bit of tongue work? you thought i’d just let you go with some  _ head?” _

 

Papyrus swallows. “M-mi’lord?”

 

“no, no, no. you promised, papyrus.” Sans runs a phalange on his scarred socket and watches the guilt shadow his mutts' face. “you have so many sins, brother, and i’ve managed to overlook all of them and love you. why can’t you love me too?”

 

“I-I’m so sorry, mi’lord I didn’t mean to I love you I do I’ll do whatever you ask please please-” 

 

“shhhh,” Sans relaxes the leash and cups Papyrus’ skull. “shhhh, i know you didn't mean to, brother. you just forgot, that’s all. it’s alright. i only want you to be happy, papyrus. as your owner i only want what’s best for you.”

 

Papyrus mumbles frantically under his breath, grasping at Sans hand, taking heaving panicked breaths. He’s so beautiful. Sans trails his fingers down the badly healed cracks on his brothers skull, remembering the pain, the anger, the  _ betrayal of his property _ . It was truly fortunate Papyrus had such excellent control of his magic or Sans would have been dust that day. And where would Papyrus be without his guidance?

 

“it’s alright. just do what I trained you, okay?”

 

Papyrus takes some steadying gasps and nods. The true threat, the heavy guilt of his promise, fading in the focus of his training. He looks down at his pelvis and swallows. 

 

“Mi’lord may… may I…?” He trails off, still shy about it. How cute. 

 

Sans shuffles on the couch, leaning his shoulders against the arm and jerks the leash. Papyrus stands and clambers over him to settle his legs on either side of his hips. Sans squirms at the weight, and gives his brother a smile. Papyrus returns it shakily, spit and arousal drying on his chin. Sans’ arousal never abated but Papyrus obviously needs some encouragement. Fortunately, Sans trained several responses into his mutt.

 

Sans reaches up to his brothers ribs, tracing the carvings he had made. Hours and hours, days and days of slowly cutting and letting it heal and doing it all over again. The designs range from flowers to random geometrics but there is one, sloppily carved on the right floating rib that is his favourite. It’s crude, uneven, and written in his own rounded font.

 

_ Sans. _

 

A true brand. Done in the heat of the moment but all the sweeter for it. Marking what is his. Sans traces the letters, Papyrus’ hands clench though he doesn't move otherwise. Sans smiles and  _ digs. _

 

The carvings are thick with old growth, a lumpy uneven mess and it takes effort to break through the scarred bone. Papyrus groans, pelvis grinding. Sans breathes as his fingers sink into the bone, watching the letters darken with marrow. The bone cricks and grinds and bleeds. He moves to the next letter, marrow splattering against Papyrus’ pelvis and painting him so pretty. His mutts' magic is already reacting, the response well trained into him.

 

“ _ Hahhh,  _ mi’l- _ AH!” _

 

A particularly violent jerk rubs Papyrus’ pelvis against Sans’ conjured genitals and they both moan. Papyrus’ magic thickens and he whines, pushing his ribs into Sans slow carving.

 

“ _ thah- _ that’s good, you’re so good, mutt. just a little-  _ hahhh-  _ little more.”

 

“Mi’lord  _ please _ !”

 

Sans pulls out his claws, dripping marrow, and wraps his hand around Papyrus’ spine, squeezing. 

 

“ah, there you are.”

 

He gentles his grip and rubs his brothers uneven spinal column. Papyrus gasps, hips jerking as the dribbling marrow from the carved brand splatters against his new member. Sans tugs the leash and Papyrus groans, planting his hands on either side of his owner. Sans lifts his legs, bowing his spine, and wraps them around his brothers’ waist. Papyrus, flushed and gasping waits and Sans feels pride in his mutt. 

 

“do it, you know you want to.”

 

His brother groans and reaches down a hand to guide himself inside Sans. He thrusts and the head slides through with ease.

 

“ _ ah, papyrus!”  _ Sans clenches and Papyrus move shallowly, sinking a little bit deeper with each pass. Sans moans and reaches up to his brothers shoulders, digging into his scapula. Papyrus hisses and jerks violently, bottoming out. He pauses, staring somewhere over Sans. Sans gazes at his brother, feeling full and heavy and wet and  _ ready. _

 

Papyrus starts slow, as always, so careful and considerate. Drawing almost completely out before filling him back up. The slow, leisurely glide is torture. Feeling the thick weight ever so slowly stretch him out, rubbing and sliding against his inner walls. Then draw back and leave him empty, clenching on nothing. Sans moans as Papyrus thrusts again.

 

“ _ hah hah- please, brother.”  _ He gasps, clenching down, feeling so  _ full. _

 

“A- _ ah _ as mi’lord C- _ hahh _ -commands.”

 

Papyrus braces himself on his elbows, so much taller, Sans stares at his collarbone in it's branded glory. He sets a punishing pace, the couch shuddering at their movements. Sans’ spine is shoved against the arm of the furniture and he gasps, mouth open as he pants. Papyrus reaches down, bracing himself on one elbow and thumbs Sans clit. 

 

“ _ ah! ah! _ ” He clenches, digging his fingers into Papyrus’ scapula and feeling bone give. Pleasure builds, sparking up his spine, sinking deep into his pelvis. “y-you  _ hah  _ aren’t allowed t-to c- _ ah- _ come until i  _ ngh!  _ until i do.”

 

Papyrus grunts. “Y-Yes, mi’lord.”

 

The asshole starts rubbing Sans’ clit with every thrust and Sans groans. He curls his toes, feeling the pleasure tighten, cresting. His own movements get sloppy, the slide of Papyrus’ dick heavy. Sans pulls the leash and Papyrus bends down obediently. 

 

“ _ ngh ah! ah _ ! bite!”

 

Papyrus sinks his teeth into Sans’ collarbone, metal fangs going deep. Sans comes with a howl, hips jerking. Papyrus fucks him through it, panting through his mouthful of bone. Sans let's up on the leash, panting, legs twitching. Papyrus moans and pulls back to pound through the small aftershocks to his own release. Sans gasps when his brother thrusts deep, dick twitching as hot cum fills him up. He pulls out, member slick and flops sideways on the couch, panting. Sans winces at the feeling of cum trickling out of him. Bleh, the worst part.

 

“such a good job, mutt.”

 

“Th-thank you, mi’lord.”

 

Sans shuffles so he’s facing Papyrus and snuggles into his marrow splattered sternum. Papyrus wraps his arms around him, placing his chin on Sans’ skull. 

 

“maybe i'll teach those stupid kids a lesson by taking one for supper tomorrow.”

 

“W-will mi’lord still be taking me?”

 

Sans snorts. “of course. can’t restrain someone myself.”

 

“Good.” Papyrus yawns.

 

“go to sleep, mutt.”

 

“M’kay, mi’lord.” He trails off into snores and Sans is, once again, amazed at how quickly he can fall asleep. He runs a finger along the sluggishly leaking brand on his floating rib.

 

_ Sans. _

 

“you’re mine. gaster said so. gaster gave you to me and said “here, it’s yours now” and that means i own you. it means you’ll never, ever leave me.” He traces the words, his words, smearing the marrow across them. He smiles.

 

_ Papyrus LV 5 HP 1280/1300 _

_ Yours. _

  
  
  
  
  
  
  
  
  


**Author's Note:**

> barkingpup49.tumblr.com I also have a Ko-Fi and I now take commissions, including NSFW.
> 
> This whole thing is how I perceive Swapfell, personally. I may write more as I have some good ideas but for now I'll leave it as a smutty One-Shot.
> 
> OMIGOSH I GOT FANART GO SEE THIS AMAZINGNESS  
> https://utfruitsaladmystuff.tumblr.com/post/159234066884/papyrus-lv-5-hp-12801300-yours-so-ive-been


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